1. Field of the Invention
This invention relates to a heating apparatus including a heater provided for heating food by means of hot air or radiant heat, and more particularly to such a heating apparatus wherein a heating period of time is automatically set.
2. Description of the Prior Art
The prior art has provided for a heating apparatus in which a build-up characteristic of the temperature in a heating chamber is detected after the initiation of a heating operation in order that a heating time period can be automatically set. The detection of the build-up characteristic of the temperature in the heating chamber relies upon that it is dependent upon an amount of food to be cooked. In this type heating apparatus, a heater is energized to start the heating upon start of the cooking. Measurement is executed as to a period of time from the start of the cooking to a time the temperature in the heating chamber reaches a predetermined control temperature. A heating period of time is set in accordance with the results of the measurement. The heater is deenergized for completion of the heating when the set cooking time period has elapsed.
In the above-described heating apparatus, however, it takes much time for the temperature in the heating chamber to reach the control temperature when an amount of food to be cooked is relatively large. Accordingly, there is a problem that a user is informed of a remaining time period too late.
Furthermore, an initial temperature in the heating chamber is shifted largely from the normal state when an atmospheric temperature is very high or very low or when the cooking is repeated at short intervals. In such a case, the the heating time period automatically set on the basis of the detected temperature is also shifted largely from an optimum heating time period. Consequently, there arises a problem that an error in the automatically set heating time period is increased.